Title in author's pseudonym name

[Emmy]

The Librarian Manual clearly states that titles, degrees etc. are not to be included in the author name (unless necessary to avoid confusion, or if part of a recognized pen name.

This author also uses the pseudonym 'Sir Steve Stevenson' author of the "Agatha: Girl of Mystery" series but has also on the pseudonym's profile books that 'merely' mention 'Steve Stevenson' on their cover, e.g. the Scuola dei pirati series.

Should the 'Sir' be eliminated from the pseudonym's name?

[Arenda]

Emmy wrote: "but has also on the pseudonym's profile books that 'merely' mention 'Steve Stevenson' on their cover, e.g. the Scuola dei pirati series."

As far as I can see, that is only on the Spanish editions.

The author is Italian and the Italian editions have Sir on the cover: